The present invention relates to a removable roof for a vehicle and a method of making a removable roof.
Removable roofs are known for use in conjunction with convertible vehicles including premium vehicles such as the BMW 325 CI, BMW Z3, and as disclosed in U.S. Pat. No. 5,489,146 to Fischbach. Removable hard tops address one drawback of convertible vehicles by providing a durable top for a vehicle during the winter months while the convertible top may be kept in its stowed position protecting it against the elements.
Prior art removable hard tops are normally built on a frame having multiple components to which rigid panels are assembled. In an effort to improve rollover protection, metal roll bars may be incorporated into the removable roof structure or an active roll bar system may be incorporated in other portions of the passenger compartment. Removable tops having a separate frame are expensive to manufacture and are relatively heavy. As vehicles are normally assembled there is a limited amount of twisting and tolerance stack up that can result in variances in vehicle mounting locations that can complicate securing a removable roof to the vehicle.
Styling requirements may limit the space available for hold down clamps used to secure the sides of a removable top to a vehicle. The inclusion of side windows in a removable top imposes substantial limitations on the space available for hold down clamp assemblies. While it is desirable to provide larger, more robust hold down clamp assemblies, space limitations and weight reduction considerations provide challenges in the design of removable vehicle roofs and their associated hold down clamp structures.
These and other problems and challenges are addressed by Applicant""s invention as summarized below.
According to the present invention, a method of making a removable roof for a vehicle is provided. The method includes forming an outer panel of the roof in a heated mold from a sheet of thermoset plastic resin having fiber reinforcement material distributed in the resin. The thermoset plastic resin sheet is formed in the mold to the net size and shape of the roof outer panel. An inner panel of the roof is similarly formed in a second mold from a second sheet of thermoplastic resin with fiber reinforcement material distributed in the resin. The second sheet is formed to the net size and shape of the roof inner panel. The inner and outer roof panels are both trimmed and assembled to appropriate mounting brackets and locking assemblies that are assembled to the inner roof panel. The roof outer panel and roof inner panels are bonded together to form a removable roof for a vehicle.
One aspect of the invention is the formation of an integral roll bar on the roof inner panel as the roof inner panel is molded. The integral roll bar is designed to withstand a 5,000 pound load or one and one half times the unloaded vehicle weight, whichever is less.
According to another aspect of the invention, the inner and outer roof panels are formed from sheets of a sheet molding compound of thermoset plastic resin that is reinforced with either glass fibers, carbon fibers, polyacrylonitrile or a combination thereof.
According to the invention, a removable roof for a vehicle is provided for a vehicle having a windshield including a header on an A pillar located in front of the front vehicle doors and a B pillar located in front of and rearward of the front vehicle doors, respectively. The removable roof has a fiber reinforced thermoset resin inner and outer panel. The inner panel preferably includes an integrally formed roll bar. The removable roof for a vehicle is detachably secured to the vehicle by means of four attachment points two of which are right and left hold down clamp assemblies that are secured to hold down bracket assemblies that are secured to the B pillar of the vehicle. A windshield header attachment bracket is secured to a front portion of the inner roof panel. Right and left roof hold down clamp assemblies and right and left roof latch reinforcement plates are secured to right and left sides of the inner panel of the roof. Right and left hold down bracket assemblies each comprise an upper plate, a bracket and a lower plate that are secured together and to the B pillar of the vehicle by fasteners.
According to another aspect of the removable roof of the present invention, the removable roof may be formed with a side surface from which side window openings may be cut out after molding. The inner panel of the roof may also be formed with cavities below and forward of the side window openings in which roof hold down clamp assemblies may be secured.
According to another aspect of the invention, a pivotal shaft is rotatably retained in each of the mounting brackets wherein a cam is secured on one end to each of the pivotal shafts that are received by each of the hold down bracket assemblies. A cam follower may be attached to each of the B pillar brackets for receiving the cam of each of the pivotal shafts and providing an engagement point for the cams to pull the clamp assemblies into engagement with the hold down bracket assemblies. B pillar brackets are preferably assembled to reinforcement plates and fastener retention plates that are assembled together with fasteners that extend through fastener receptacle holes. The B pillar bracket preferably includes a horizontally extending flange, a longitudinally extending flange, and a transversely extending flange that are mounted to a horizontal edge, and longitudinal surface of the B pillar. Elongated slots preferably provided in the B pillar brackets permit adjustment of the location of the B pillar bracket fore and aft and transversely and longitudinally to compensate for variations in vehicle roof locating positions.
These and other aspects, objects and advantages of the present invention will be better understood by one of ordinary skill in the art upon review of the attached drawings and following detailed description of the drawings and of the best mode of practicing the invention.